SCS PTC-IIex, Manual

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8 FAX
The following SSTV-modes are supported by the PTC-IIex:
SMode MODE-Name
0 ALLMODE
1 MARTIN
1
2 MARTIN 2
3 SCOTTIE 1
4 SCOTTIE 2
5 SCOTTIE DX
6 8 sec / 120 line
7 16 sec / 120 line
8 32 sec / 240 line
9 WRAASE 24/128
10 WRAASE 48/128
11 WRAASE 48/256
12 WRAASE 96/256
13 WRAASE 120/256
14 WRAASE 180/256
15 ROBOT 72/256
Table 8.2: STTV sub modes
8.9.11 TXcomp
Default setting: 0
Parameter: 0 COMPARATOR Tx disabled.
1 COMPARATOR Tx enabled.
This PARAMETER-command activates (1) or de-activates (0) the TXD-modulator in the
COMPARATOR mode. With
TXcomp
switched on, it is possible for many programs that
support the HAMCOMM-modem to send FAX and SSTV direct from the PTC-IIex. The
PTC-IIex looks at the voltage appearing on the CTS-line (PIN 7 of the RS-232 interface).
When +10 volts appears, the PTT line is activated. The PTT line is de-activated (turned
off) when the voltage is -10 volts. When in the send condition, the PTC-IIex measures the
incoming data as square wave modulation data on the RxD PIN.
The zero crossing point is measured very exactly, and then modulates the VCO in the
DSP. The PTC-IIex has a very good transmit resolution even in the Simple Modem mode,
providing the PC program works as precisely. The translation of the transmit-data into a
clean analogue signal is not just through an RC low pass filter (as is usual). Instead, the
system calculates exactly the reverse of the simple demodulator principle.
8.10 LED functions
8.10.1 The LED´s whilst transmitting
The tuning indicator displays directly in every mode the output value (0-255) or input
(whilst transmitting) value (0-63). The
left-hand limit represents value zero, the right-
hand limit , the maximum value.
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